Means and method of fixing electrodes in glass tubes



Sept 9, 1930. F. B. HALE 5, 98

MEANS AND METHOD OF FIXING ELECTRODES IN GLASS TUBES Filed Nov. 27, 1928 BY j g ATTORNE Patented 9,

FRANKLYN 3. ml, or sm rnancrsco,

WILLIAM C. BRUMFIELD, OF

camrormm, assrenoa' or ONE-HALI r SAN FRANCISCO, CALIFORNIA MEANS AND METHOD OF FIXING IN GLASS 'I'tl'BES Application fled November 27, 1928. Serial No. 822,109.

My invention has. for its object the means and method of mounting an electric conductor or electrode in the walls of a glass tube and particularly a glass tube which is vacuumized or'filled with rarefied gas or gases and through which an electrical discharge is intended'to be. maintained; whereby any ex- I seal of the tube itself to cessive heat generated by the electrode is dissipated and reduces the temperature differences between that portion of the "electrode or conductor within the prevent cracking or other destructive effects that heretofore have developed such heat differences.

Other objects will appear from the drawing and specifications which follow:

These objects I attain by mounting the electrode upon a conducting wire and advancing the conducting wire a material distance within the t be beyond the sealed joint between the conductor and the tube and also mounting on said inner portion of the conductor a heat conducting body 1n contact with the conductor adjacent to the electrode and within the tube and adapted to convey and dissipate the heat proceeding from the electrode towards the seal in the tube and therefore to by-pass the heat from the said conductor and tube seal.

By referring to the accompanying dra wmy invention will be made clear: l

n the drawing Fig. 1 is a section of one end portion of a vacuum tube which may be of. any,form, and in which an charge is adapted to be maintained and showing in detail my invention applied thereto and employing a different form of electrode from that of the other figures. Fig. 2 is a side View of a tube to which my invention-is applied. v

Fig. 3 is one form of an electrode with its conductor as first prepared.

Fig. 4 is the electrode and conductor of Fig. 3 to which the heat dissipating member has been applied, prior to introduction in the tube.

Throughout the figures similar numerals refer to identical parts.

Numeral 1 indicates a conventional glass tube adapted to contain rarefied gases and tube and the glass electric diswithin which an electric maintained between the electrodes 2 and 3, the emergin current being conveyed'thereto by the con uctors 4, 5 respectively.

t 6 is shown a thimble of glass or other heat conductive dielectric material havin a heat dissipating surface and body portionietween the seal 7 embracing the'conductor 5 and the seal 8 of the glass tube'l and embracing the conductor 5.

trode 3, the" latter becomes quite hot and materially hotter than the glass wall 1 and the metallic conductor 5.

The vacuum in 10 providesa fairly good heat insulator and therefore unless other means be rovided, excess heat is conducted from the e ectrode 3 heating the conductor 5 more highly than the glass portion of the tube embracing the conductor at the seal 8.

Although it is well recognized practice to- ;provide. the conductor 5 of material having approximately the same heat expansion coefiicient as the glass, the difference in temper-v ature above recited is frequently suflicient to cause a greater expansion on the body pordischarge may be Durlng the electric discharge from the elec- 1 tion of the conductor 5 than in the glass when the. electrode is being brought up to its temperature, or a materiall ,less temperature than the glass tube -1, af ter the current has been out off due to the more rapid dissipa tion of heat from the conductor 5 than from the glass. 1

In both cases this temperature difference is apt .to crack the glass around seal 8 and destroy the vacuum. To reduce this temperature difference between the conductor 5 and the seal 8, I provide a dielectic member 6 which may be with advantage, as here shown, formed as a glass thimble, sealed at 7 to the conductor 5, and s aced'at 11 from the said conductor and pre erably contacting as at 12 with the outer portions of the glass seal 8. Heat from the electrode 3 is then diverted at 7 as it advances along the conductor 5, and is partly dissipated from the surface 6 and is also conducted to the outer portions of the seal 8 at 12, so that the entire seal 8 is more evenly heated while the temperature 'of the conductor adjacent the seal 8, is proportionally reduced, that is the temperature difference between the glass of the seal 8 immediately adjacent the conductor 5and the conductor 5 is greatly reduced.

This reduction in temperature diflerences effected by the means 6 prevents cracking or damage of the seal at 8 and maintains more perfectly vacuum at 10, within the tube 1.

Conversely after the current has been cut off, the cooling of the conductor 5 Within the tube would be slower by the cooling of the seal 8 because of the rapid dissipation of heat from the seal ,8, whereas when my invention a is employed the conductor within the tube is cooled by the member 6 and the outer portions of the seal 8 are retained relatively warmer so that the entire body of the seal 8 reduces in temperature more nearly at the L same rate as the conductor 5.

It will now be seen that by my invention the entire body of the seal 8 is retained more nearly at the temperature of the conductor 5 where it passes through the seal8 during the adjacent said seal, then exhausting said tube andthen introducing a small quantity ofan inert gas adapted toexhlbit luminescence upon an electric discharge from said electrode.

. FRANK LYN B. HALE.

heating and during the cooling and during 7 variations in the energization of the tube 1.

- Reference is herein made to my copending application Serial No. 322,108 filed November 27, 1929, wherein is claimed certain matter herein disclosed.

I claim:

1. In combination with an electrode sealed in a tube and having a conducting stem, a

- separate member of heat conducting material within said tube positioned about said stern and spaced therefrom and a seal between 1 said stem and said member adjacent the electrode. I

2. In combination with an electrode sealed in a tube and having a conducting stem, a glass thimble positioned about said stem and spaced therefrom and a seal between said stem andsaid thimble adjacent the electrode.

3. In a luminescent gas tube the combination set forth in claim'1 wherein one end of said memberis in physical contact with a portron of said tube.

t. In a luminescent gas tube the combination set "forth in claim 2 wherein one end of said thimb le is in physical contact with portion ofsaid tube.

5. The method of reducing the heat trans ter from an electrode having a stem to a sealed portion positioned between a glasstube and said'stem which consists or mounting a heat conductor spaced about said stem with in said tube one end of said conductor sealed to said stein adjacent the electrode and the other end in physical contact withsaid sealed portion between the glass tube and the con ructor remote from said conductor, y

6; The method ofproducing a luminescent gas tube with an electrode mounted on a stem 7 which consists of sealing a heat conductor oit greater internal 'diameter than said stem to said stem adgacent said'electrode then sealing 

